Technique for using a dialysis machine to disinfect a blood tubing set

ABSTRACT

A method of disinfecting a blood tubing set on a dialysis machine after the blood tubing set has been used in a dialysis treatment. One end of the blood tubing set is connected to a disinfection port on the dialysis machine and an opposite end of the blood tubing set is connected to a waste drain. The dialysis machine provides a supply of a disinfectant solution to the disinfection port. A blood pump on the dialysis machine pumps the disinfectant solution from the disinfection port to the waste drain through the blood tubing set to expel contaminants from the blood tubing set. The blood tubing set is preferably connected to a dialyzer which is disinfected when the disinfectant solution is pumped through the blood tubing set. A supply of cleaning solution or water may be pumped through the blood tubing set and dialyzer to expel the disinfectant solution. A supply of air may be pumped through the blood tubing set and dialyzer to expel substantially all fluid from the blood tubing set and dialyzer. A dialysis machine includes hydraulic components for mixing and heating the disinfectant and cleaning solutions and for supplying the disinfectant solution, the cleaning solution, water and air to the disinfection port.

This is a divisional of application Ser. No. 08/481,754, filed Jun. 7,1995, issused as U.S. Pat. No. 5,685,835, on Nov. 11, 1997.

The present invention relates to a new and improved dialysis machine andtechnique for cleaning and disinfecting a disposable blood tubing setwhich connects a patient to the machine.

CROSS REFERENCE TO RELATED INVENTIONS

This invention is related to the inventions described in U.S. patentapplications for Technique for Automatically Preparing a DialysisMachine at a Predetermined Date and Time, Ser. No. 08/484,013, now U.S.Statutory Invention Registration No. H1658, published Jul. 1, 1997; andTechnique for Priming and Recirculating Fluid Through a Dialysis Machineto Prepare the Machine for Use, Ser. No. 08/481,755, now U.S. Pat. No.5,650,071, issused Jul. 22, 1997, both of which were filed concurrentlytherewith. Both of these applications are further assigned to theassignee hereof. The disclosures of these applications are furtherincorporated herein by this reference.

BACKGROUND OF THE INVENTION

A dialysis system is used as a substitute for the natural kidneyfunctions of a human body. The dialysis system cleans the blood of thenatural accumulation of bodily wastes by separating the wastes from theblood outside or extracorporeally of the body. The separated wastes aredischarged and the cleansed blood is returned to the body.

The dialysis system consists of a dialysis machine, a dialyzer, adisposable blood tubing set and a supply of chemicals for producing adialysate solution used within the dialyzer. The dialyzer is used withthe dialysis machine to separate the wastes from the blood. The dialyzerincludes a porous membrane located within a closed housing whicheffectively separates the housing into a blood compartment and adialysate or filtrate compartment. The blood removed from the patientflows through the disposable blood tubing set and the blood side of thedialyzer. The dialysate solution prepared from the chemicals is passedthrough the dialysate side of the dialyzer. The wastes from the bloodpass through the membrane by osmosis, ionic transfer or fluid transportinto the dialysate and, depending upon the type of dialysis treatment,desirable components from the dialysate may pass in the oppositedirection through the membrane and into the blood. The transfer of thewastes into the dialysate cleanses the blood while allowing the desiredcomponents from the dialysate to enter the bloodstream.

The transfer of blood between the patient and the dialyzer occurs withina disposable blood tubing set. The blood tubing set and the dialyzerrepresent a closed extracorporeal path through which the patient's bloodtravels. The blood tubing set includes an arterial line connected to anarterial reservoir for drawing blood from a patient, a venous lineconnected to a venous reservoir for returning blood to the patient, anda number of other lines for connecting a pump and the dialyzer betweenthe arterial and venous reservoirs. Before the blood tubing set and thedialyzer can be used in a dialysis treatment, both must be primed with asterile saline solution to remove air from the extracorporeal circuit.Once primed, the saline solution is recirculated through the bloodtubing set and the dialyzer to produce a stabilized flow and removeadditional trapped air from within the extracorporeal circuit. Thepriming and recirculating process also serves to clean the dialyzer andflush the dialyzer membrane of any debris or chemicals remaining from aprior use.

If a patient reuses the same dialyzer for subsequent dialysistreatments, that dialyzer must be cleaned with a disinfectant orsterilant solution. However, the sterilant itself must be cleaned fromthe dialyzer prior to each dialysis treatment. Such a cleaning procedureeffectively takes place when the dialyzer undergoes the priming andrecirculating process discussed above.

After completion of the prime and recirculation steps (i.e., when theblood tubing set is filled with saline), the arterial line of the bloodtubing set is connected to the patient in the usual manner of dialysissystems. Blood is then drawn from the patient into the arterial line bya blood pump. The blood tends to replace the saline within the bloodtubing set, and the saline is discarded down a waste drain until theblood tubing set is substantially filled with blood. The venous line isthen connected to the patient to complete the extracorporeal circuit andallow the blood to travel through the arterial line, the dialyzer andback to the patient through the venous line.

At the conclusion of the dialysis treatment, but before the patient iscompletely disconnected from the dialysis machine, blood remaining inthe blood tubing set must be returned to the patient. This is typicallyaccomplished in one of two ways. One procedure requires clamping anddisconnecting the arterial line from the patient and then attaching thearterial line to a saline source. The arterial clamp is then opened andthe blood pump is started to draw saline into the arterial line andforce the remaining blood through the arterial line, the dialyzer, andthe venous line and back into the patient. When substantially all theblood has been returned to the patient, the venous line is clamped andthe pump is stopped. The patient can then be disconnected from thedialysis machine.

Another procedure for returning the blood remaining within the bloodtubing set to the patient entails using the same saline source that isused to prime the blood tubing set. The saline source is connected tothe arterial reservoir of the blood tubing set and the saline is gravityfed into the arterial reservoir to force the blood in the arterial lineback into the patient. Once the blood within the arterial line has beenreturned to the patient and the arterial reservoir has been filled withsaline, the arterial line is clamped and the blood pump is activated topump the saline through the dialyzer and the venous reservoir to forcethe remaining blood back into the patient through the venous line. Oncesubstantially all the blood has been returned to the patient, the venousline is clamped and the patient is disconnected from the dialysismachine.

Although both procedures return substantially all the patient's blood,neither procedure returns 100% of the blood. Thus, the saline within theblood tubing set is contaminated with the patient's blood. The bloodtubing set is thus usually discarded with the remaining contaminatedsaline left inside.

Due to the contaminated saline, the blood tubing set is necessarilyclassified as bio-hazardous medical waste which is relatively expensiveto dispose of in comparison to normal refuse. Bio-hazardous medicalwaste cannot be discarded as normal trash, but rather must be sealed andremoved by special contractors. Hospitals and dialysis clinics musttypically pay a premium price for every pound of medical waste. Sincethe used blood tubing set is typically filled with contaminated saline,this "water weight" significantly increases the disposal cost of theblood tubing set.

Additionally, if the dialyzer is to be reused, it must be detached fromthe blood tubing set before the set is discarded. This is typicallyaccomplished by clamping the blood tubing set at the inlet and theoutlet of the dialyzer so that the dialyzer can be detached withoutspilling the contaminated saline remaining within the blood tubing set.The dialyzer can then be reprocessed after the blood tubing set isdiscarded, but the dialyzer must be handled carefully due to thecontaminated saline remaining within the blood compartment of thedialyzer.

Some clinics have attempted to recycle the blood tubing set togetherwith the reusable dialyzers. However, reprocessing the dialyzer entailsconnecting the dialyzer to a different machine which can flush sterilantthrough the dialyzer. Thus, recycling the blood tubing set with thedialyzer requires extending the functionality of the dialyzer flushingmachine to also flush the contaminated saline from the blood tubingsets. Two potentially serious problems may be associated with thisrecycling method. First, the dialyzer flushing machine is not adapted tohandle the blood tubing set and thus the time and effort required toclean the blood tubing set on the machine is typically notcost-effective in relation to the cost of a new disposable blood tubingset. Secondly, and potentially more serious, the operator is required tohandle the contaminated blood tubing set in an environment which themanufacturers of the "disposable" blood tubing set did not intend,thereby exposing the operator to very serious health risks.

These and other considerations have contributed to the evolution of thepresent invention which is summarized below.

SUMMARY OF THE INVENTION

One of the significant aspects of the present invention pertains to amethod of disinfecting a contaminated blood tubing set while the bloodtubing set remains attached to a dialysis machine following a dialysisprocedure. Another significant aspect of the present invention relatesto disinfecting a blood tubing set without requiring a dialysis machineoperator to substantially handle the contaminated blood tubing set afterthe patient has been disconnected from the blood tubing set. A furthersignificant aspect of the present invention relates to disinfecting ablood tubing set so that the blood tubing set may be discarded as refuserather than bio-hazardous medical waste. A still further significantaspect of the present invention pertains to disinfecting a dialyzer inconjunction with a blood tubing set so that the dialyzer may be safelyhandled by the dialysis machine operator. A further aspect of thepresent invention pertains to expelling a majority of the fluid within ablood tubing set and a dialyzer to enhance the handling and the disposalcost of the blood tubing set and dialyzer.

In accordance with these and other aspects, the present invention may begenerally summarized as a method of disinfecting a blood tubing setwhich has been contaminated with a patient's blood following a dialysisprocedure. The blood tubing set is typically filled with saline at theconclusion of a dialysis treatment to return the patient's bloodremaining within the blood tubing set and the attached dialyzer.Following disconnection from the patient, one end of the blood tubingset is preferably attached to a disinfection port on the dialysismachine while the opposite end of the blood tubing set is attached to awaste drain. The dialysis machine provides a supply of a disinfectantsolution to the port and then pumps the solution through the bloodtubing set and the dialyzer to flush the contaminated saline within thedialyzer down the waste drain. The disinfectant solution is preferablyheated by a heater within the dialysis machine.

The method of the present invention also provides for the dialysismachine to pump other solutions through the blood tubing set, such aswater, bleach (or other cleaning solutions), or even air. For instance,a water rinse may be provided to flush out the disinfectant solutionafter the disinfectant solution has flushed the contaminants from theblood tubing set. Additionally, air may be pumped through both the bloodtubing set and the dialyzer to substantially remove the fluid from theblood tubing set and the dialyzer before they are detached from thedialysis machine.

The present invention also includes a dialysis machine capable ofsupplying the desired disinfectant solution to the blood tubing set. Thedialysis machine preferably utilizes a number of hydraulic elementswhich are also utilized to create the dialysate used to cleanse thepatient's blood during the dialysis treatment. These hydraulic elementsinclude a water source and a heater for mixing and heating thedisinfectant solution and for rinsing the disinfectant solution from theblood tubing set. The dialysis machine also includes a source of airwhich may be used to substantially purge the blood tubing set and thedialyzer of fluid.

The dialysis machine also preferably transfers the disinfectant solutionto the blood tubing set from a disinfection port which is easilyaccessible to the dialysis machine operator. Additionally, the dialysismachine preferably includes a waste handling port so that the operatormay conveniently attach the blood tubing set between the disinfectionport and the waste handling port (after detaching the blood tubing setfrom the patient) with minimal risk of being exposed to the contaminatedfluid within the blood tubing set.

A more complete appreciation of the present invention and its scope maybe obtained from the accompanying drawings, which are briefly summarizedbelow, from the following detailed descriptions of presently preferredembodiments of the invention, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dialysis machine which incorporatesthe present invention.

FIG. 2 is a generalized view illustrating a dialyzer, an extracorporealblood flow path from a patient through the dialyzer, and a dialysateflow path through the dialyzer, as are present during treatment of apatient with the dialysis machine shown in FIG. 1.

FIG. 3 is a generalized view of a dialyzer connected to a blood tubingset which together define the extracorporeal flow path shown in FIG. 2,and illustrating a saline source connected to the blood tubing set atthe conclusion of a dialysis treatment forcing blood remaining withinthe blood tubing set to return to the patient.

FIG. 4 is a generalized view similar to FIG. 3, illustrating the salinesource working with a blood pump shown in FIG. 2 to force the remainderof the blood within the extracorporeal flow path to return to thepatient.

FIG. 5 is an expanded view of the dialysate flow path shown in FIG. 2(including the dialyzer), where the extracorporeal blood flow path hasbeen omitted for clarity.

FIG. 6 is an expanded view of the dialysate flow path similar to FIG. 5,illustrating additional hydraulic components including a disinfectionport of the present invention for disinfecting the blood tubing setshown in FIG. 2.

FIG. 7 is a generalized view similar to FIG. 3, illustrating thedisinfection port shown in FIG. 6 connected to the extracorporeal flowpath shown in FIG. 2 for disinfecting the blood tubing set.

DETAILED DESCRIPTION

An example of a dialysis machine with which the present invention may beadvantageously employed is shown at 30 in FIG. 1. The dialysis machine30 includes an enclosure 32 to which are attached, or within which arehoused, those functional devices and components of the dialysis machine30 which are generally illustrated in FIG. 2. The enclosure 30 alsoincludes a conventional input/output ("I/O") device for controlling themachine 30, such as a touch-screen monitor 33 as shown in FIG. 1.

The dialysis machine 30 includes at least one blood pump 34 whichcontrols the flow of blood from a patient 36. An arterial line or tubing38 is connected through an arterial clamp 40 to a blood handlingcartridge 42. The blood handling cartridge 42 is normally retainedbehind a door 44 (FIG. 1) of the machine 30 when used, thus the bloodhandling cartridge 42 is not shown in FIG. 1. The blood pump 34 also islocated behind the door 44 adjacent to the cartridge 42. The blood pump34 in dialysis machines is typically a peristaltic pump.

The patient 36 is connected to an extracorporeal flow circuit by anarterial connector 37 and a venous connector 39. Blood from the patient36 flows through the extracorporeal circuit when the arterial clamp 40is open and the blood pump 34 draws blood from the patient 36. The bloodpasses through the arterial line 38 and into an arterial reservoir 46 ofthe cartridge 42. The blood pump 34 draws blood from the arterialreservoir 46 through a pump header 48 which is squeezed or pinched by arotating rotor 49 against a stationary raceway 50, in the typical mannerof peristaltic pumps. The blood within the pump header 48 which isrotationally in front of the rotor 49 is propelled through the pumpheader 48 and into a manifold 51 of the cartridge 42. A tubing 52conducts the blood from the manifold 51 of the cartridge 42 into a bloodinlet 53 of a conventional dialyzer 54. A microporous membrane or othertype of dialysis medium 56 divides the interior of the dialyzer 54 intoa blood chamber 58 and a dialysate chamber 60.

As the patient's blood passes through the dialyzer 54, the wasteproducts within the blood pass through the medium 56 where they mix withthe dialysate in the chamber 60. The cleansed blood exits the dialyzer54 through a blood outlet 61 and is then transferred through a tubing 62to an inlet 63 of a venous reservoir 64 of the cartridge 42. Any airwhich might have been unintentionally introduced into the blood iscollected and removed while the blood is in the venous reservoir 64.Blood exits the venous reservoir 64 through an outlet 65 and is removedfrom the cartridge 42 through a venous tubing or line 66.

After leaving the venous reservoir 64, the blood flows through thevenous line 66 to an air detector 70. The air detector 70 derivessignals related to the quantity of air, if any, remaining in the venousline 66. If an excessive or dangerous amount of air is present, a venousline clamp 72 will immediately close and the blood pump 34 will stop toterminate the flow of blood through the venous line 66 before thedetected air reaches the patient 36.

The enclosure 32 of the dialysis machine 30 also encloses the variouselements of a dialysate flow path, shown in abbreviated form in FIG. 2.The elements of the dialysate flow path include a number of differentvalves (most of which are not shown) and a dialysate pump 74 which drawsdialysate from a container 76 or from an internal supply of dialysatewhich the dialysis machine 30 has prepared from appropriate chemicalsand a supply of purified water.

The dialysate pump 74 draws the dialysate from the supply 76 anddelivers the dialysate through a dialysate supply tubing or line 78 toan inlet 79 of the dialysate chamber 60 of the dialyzer 54. Thedialysate flows past the medium 56 where it absorbs the waste productsfrom the blood in the blood chamber 58. Any beneficial components withinthe dialysate which are desired to be transferred to the blood passthrough the medium 56 and enter the blood in the blood chamber 58. Thedialysate containing the waste products then exits the dialysate chamber60 through an outlet 81 and is removed from the dialyzer 54 through adialysate waste tubing or line 82 by operation of a drain pump 84.

Prior to reaching the dialyzer 54, a heater 80 heats the dialysate tonormal human body temperature. Because the dialysate and the blood willreadily transfer heat across the medium 56 within the dialyzer 54, it isimportant that the dialysate be at body temperature to prevent excessiveheat transfer to or from the patient.

The dialysate removed from the dialyzer 54 is delivered through thewaste tubing 82 to a waste basin or drain 86. The waste drain 86 may bea separate container which receives the used dialysate and accumulatedwaste products, or it may simply be a drain to a public sewer. Thevarious valves and pumps which control the dialysate flow path arereferred to generally as the dialysate hydraulics.

Because the blood in the extracorporeal flow path is prone to clot, itis typical to inject an anticoagulant such as heparin into theextracorporeal flow path. The typical approach to injecting theanticoagulant is to slowly deliver it from a syringe 89. A plunger 90 ofthe syringe is slowly and controllably displaced into the syringe 89 bya linear driver mechanism (not shown), which is typically referred to asthe anticoagulant pump. Anticoagulant from the syringe 89 is introducedinto the manifold 51 of the cartridge 42 through a tubing 92 connectedto the syringe as shown in FIG. 2. The anticoagulant pump is controlledto deliver the desired amount of anticoagulant during the dialysistreatment by the degree to which the anticoagulant pump moves theplunger 90 into the syringe 89 over a given time period.

Tubings 94 and 96 are respectively connected to the arterial reservoir46 and venous reservoir 64 of the cartridge 42 as shown in FIG. 2.Clamps or caps (not shown) are connected to the ends of the tubings 94and 96 to selectively vent accumulated air from the reservoirs 46 and64. A saline tubing 98 is also connected to the arterial reservoir 46 sothat saline may be directly administered to the patient during treatmentin case of low blood pressure. A pole 99 for supporting a conventionalsaline bag is attached to a side of the enclosure 32, as shown inFIG. 1. Additionally, medicines or other additives may be introducedinto the blood through the access tubing 94 during treatment.

The reservoirs 46 and 64 and the manifold 51 of the blood handlingcartridge 42, together with the tubes 38, 48, 52, 62 and 66, arecollectively referred to as a blood tubing set ("BTS"). The BTS isdisposable and is typically thrown away after each dialysis treatment.Similarly, the dialyzer 54 is termed a disposable product, although itis not uncommon for a dialyzer to be reused with a single patient. Adialyzer will typically be reused by a patient who regularly visits thesame clinic for dialysis treatments. Following each treatment, thedialyzer is cleaned with a sterilant and is then stored until thepatient's next visit to the clinic. The dialyzer must then be thoroughlycleaned before use to ensure that the sterilant is not transferred tothe patient's bloodstream during the next dialysis treatment.

Before each treatment, the disposable BTS and the dialyzer 54(regardless of whether the dialyzer is new or "used") must be attachedto a dialysis machine 30 and prepared for a patient's use by anoperator. While the disposable BTS is sterile and thus does not need tobe cleaned, the BTS and the dialyzer 54 must be primed with a sterilesaline solution to remove the air from the extracorporeal circuit. Inaddition to flushing the dialyzer 54 with saline solution duringpriming, the saline solution must be recirculated through the dialyzerfor a predetermined period of time to ensure that substantially all ofthe sterilant or other chemical debris within the dialyzer has beenremoved. This recirculation process also establishes a stable flowwithin the extracorporeal circuit and ensures that any remaining airwithin the circuit has been removed before the patient is connected tothe machine 30. Once the priming and recirculating process is completedand the circuit is filled with saline, the arterial connector 37 isattached to the patient and the patient's blood is drawn through thecircuit. The venous line 66 is connected to the waste drain 86 todispose of the used saline solution and, at the point the patient'sblood has displaced all the saline within the circuit, the venousconnector 39 is connected to the patient, as shown in FIG. 2.

The same saline source used to prime the BTS is also preferably usedduring the dialysis treatment to mix saline with the patient's bloodwhen the patient experiences low blood pressure. This saline sourcetypically comprises a saline bag 100 (FIGS. 3 and 4) which is attachedto the pole 99 (FIG. 1) on the dialysis machine 30. A tube 101 connectsthe saline bag 100 to the saline tubing 98 that leads to the arterialreservoir 46.

The saline bag 100 may also be used at the conclusion of the dialysistreatment to return the blood 102 remaining within the BTS to thepatient. When used in this manner, a clamp on the tube 98 or the salineline 101 may be opened after the blood pump 34 is halted at theconclusion of the dialysis treatment. Gravity will then operate to drawsaline 103 from the bag 100 into the arterial reservoir 46 (FIG. 3) andforce the blood remaining within the arterial reservoir 46 and thearterial line 38 back into the patient 36. The arterial clamp 40 is thenclosed so that the arterial connector 37 may be removed from the patient(FIG. 4). Next, the blood pump 34 is started to draw saline 103 from thearterial reservoir 46 and the bag 100 through the dialyzer 54 and thevenous reservoir 64. Pumping saline 103 from the bag 100 in this mannereffectively "chases" the remaining blood 102 through the extracorporealcircuit so that the blood is forced through the venous line 66 and backinto the patient 36. Once the saline 103 has displaced substantially allthe blood 102 from the BTS, the venous clamp 72 is closed so that thevenous connector 39 may be detached from the patient.

Although using the saline bag 100 is the preferred method of "chasing"the patient's blood out of the BTS, an alternative method of attaching aseparate saline source to the arterial connector 37 and operating thepump 34 may also be used. All of the blood remaining within the BTSwould then be "chased" around the entire extracorporeal circuit beforebeing forced back into the patient through the venous line 66. However,this alternative method is not preferred because it requires thedialysis machine operator to physically connect the contaminatedarterial connector 37 to an additional saline source.

Once the patient 36 is detached from the arterial and venous connectors37 and 39, respectively, the dialysis machine 30 may be commanded toclean and disinfect the BTS before the BTS is detached from the machine.While the dialysate hydraulics and the BTS normally comprise completelyseparate flow paths (separated by the membrane 56 within the dialyzer 54during the dialysis treatment), the dialysate hydraulics may beconnected directly to the BTS for the limited purpose of cleaning anddisinfecting the BTS before it is discarded. However, unlike the BTSwhich is discarded after each use, the dialysate hydraulics are reusedand are typically cleaned and disinfected only once at the beginning ofeach day, and thus it is important to prevent the BTS from contaminatingthe dialysate hydraulics. Details regarding a technique forautomatically cleaning and disinfecting the dialysate hydraulics may befound in the above-referenced U.S. patent application for Technique forAutomatically Preparing a Dialysis Machine at a Predetermined Date andTime, the disclosure of which was previously incorporated by reference.

The dialysate hydraulics, which were shown in abbreviated fashion inFIG. 2, are shown in greater detail in FIGS. 5 and 6, although manycomponents of the dialysis hydraulics have been omitted for clarity.When the dialysis machine 30 creates its own supply of dialysate, asopposed to using a previously prepared supply as shown in FIG. 1, thedialysate supply 76 preferably takes the simplified form shown in FIG.5. The dialysate hydraulics creates the dialysate by mixing a flow ofpurified water from a source 104 with chemicals which typically includebicarbonate and acid. Bicarbonate is pumped from a source 105 by a pumplabeled at 106 as "Pump B." Similarly, acid is pumped from a source 108by a pump labelled at 110 as "Pump A." Additionally, the water ispreferably heated by the heater 80 before it is mixed with thebicarbonate and acid within the dialysate line 78.

A number of various filters, sensors and other ancillary devices aregenerally shown at 112. A filter is typically necessary to remove anyimpurities from the dialysate before it enters the dialyzers.Additionally, the temperature, conductivity and pH level of thedialysate is sensed at 112. The sensors then control the heater 80 andthe pumps 106 and 110 to maintain the temperature and composition of thedialysate within prescribed limits. Other ancillary equipment that maybe generally represented at 112 includes bubble traps and degassingvalves to ensure that no air bubbles are sent through the dialysate line78 to the dialyzer 54.

During the dialysis procedure, the dialysate pump 74 pumps the mixeddialysate through the inlet 79 and into the dialysate chamber 60 of thedialyzer 54. The dialysate within the chamber 60 cleanses the patient'sblood across the membrane or medium 56 as the BTS (not shown in FIG. 5)delivers the blood through the blood chamber 58 (between the inlet 53and the outlet 61) of the dialyzer 54. The dialysate waste pump 84 thendisposes of the used dialysate by pumping it from the dialyzer outlet 81to the waste drain 86 through the waste line 82.

Thus, while the dialysate hydraulics are primarily responsible for thepreparation of the dialysate, they may also be beneficially used toclean and disinfect the BTS. In general, once the dialysis treatment iscomplete and the BTS is filled with contaminated saline, the arterialline 38 may be connected to the dialysate hydraulics at a point separatefrom the dialysate line 78. The dialysate hydraulics may then becommanded to produce a supply of a cleaner or disinfectant to be pumpedto the BTS by the blood pump 34. The cleaning and disinfectant solutionmay then be flushed through the BTS or, time permitting, it may beallowed to dwell within the BTS for a predetermined time. However,because the dialysis machine can not be prepared for another patientuntil the BTS is cleaned and removed from the machine, thecleaning/disinfecting solution is preferably flushed through the BTS ina relatively short time period. The dialysate hydraulics may optionallysupply air to the BTS after it has been flushed with the disinfectantsolution so that the blood pump 34 may pump the air through the BTS tosubstantially remove the solution from the BTS and the blood chamber 58of the dialyzer 54. Upon the conclusion of the disinfection procedure,the BTS may be removed from the machine without risk of exposing theoperator to the patient's blood. The BTS can then be disposed of asnormal refuse instead of bio-hazardous medical waste. Alternatively, thedialysis hydraulics may simply use air to force the contaminated fluidfrom the BTS and the blood compartment of the dialyzer to reduce theirweight without disinfecting the BTS.

The technique of the present invention requires the presence ofadditional hydraulic components not otherwise required by the dialysismachine 30 to produce and pump the dialysate through the dialyzer 54during a dialysis treatment. Due to the length of time required to cleanand disinfect the dialysate hydraulics, it is preferred that thedialysate line 78 not be utilized in the preparation of the solution fordisinfecting the BTS. Rather, a separate disinfection line 120 branchesfrom the dialysate line 78 at a control valve 122. The disinfection lineconnects with a disinfection port 124 protruding from the enclosure 32of the dialysis machine 30. As discussed in greater detail below, thedisinfection port 124 effectively connects one end of the BTS to thedisinfection line 120 to flush the contaminated saline within the BTSdown the waste drain 86 (FIG. 7).

The disinfectant line 120 preferably includes three separate controlvalves 126, 128 and 130 connected in series, as shown in FIG. 6. Thevalves 126, 128 and 130 are each respectively connected to a source ofcleaning solution or bleach 132, a disinfectant source 134 and a sourceof air 136. Pumps 138 and 140 are preferably used to supply the bleach132 and the disinfectant 134 to the valves 126 and 128, respectively.Under the control of a microprocessor (not shown), the control valves122, 126, 128 and 130 may be operated to create any desired cleaningand/or disinfection mixture within the disinfection line 120. Themixture is preferably heated by the inclusion of water from the source104 which is heated by the heater 80. A dialysis machine operator maychoose the type of cleaning/disinfecting mixture desired from the I/Odevice 33 (FIG. 1). For example, if a heated disinfectant is desired,the operator would make the proper selection from the I/O device 33 andthe microprocessor would operate the heater 80 and "Pump D" (140) toprepare the heated water and the disinfectant. The microprocessor wouldthen open the valves 122 and 128 to mix the hot water with thedisinfectant and allow the mixture to be pumped from the disinfectionport 124.

The connection of the BTS to the disinfection port 124 is illustrated inFIG. 7. The clamped arterial line 38 is preferably attached to the port124, while the clamped venous line 66 is preferably attached to thewaste drain 86. Alternatively, the venous line 66 may be attached to awaste handling port 142 (FIGS. 1 and 7) which, in turn, is connected tothe waste drain 86. Details of such a waste handling port 142 for use ona dialysis machine may be found in U.S. Pat. No. 5,041,215, entitledDialysis Unit Priming and assigned to the assignee hereof, thedisclosure of which is incorporated herein by this reference.

Once the arterial and venous lines 38 and 66 are connected as shown inFIG. 7, the operator may command the dialysis machine 30 to begindisinfecting the BTS. Depending on the type of disinfection procedurerequested, the microprocessor will open one or more of the valves 122,126, 128 and 130, and operate the pumps 138 and 140, to prepare adisinfectant solution 143 within line 120. The microprocessor will thenopen the arterial and venous clamps 40 and 72 and start the blood pump34 to draw the disinfectant solution 143 through the port 124 and intothe arterial line 38. The blood pump 34 then continues to flush thedisinfectant solution 143 through the BTS and the blood chamber 58 ofthe dialyzer 54 until all the contaminated fluid within the dialyzer andBTS has been forced through the venous line 66 and the waste handlingport 142. The BTS may then be detached from the dialysis machine 30 andthe dialyzer 54 and discarded.

If time permits, the BTS and dialyzer 54 may be flushed more than onetime with different combinations of solutions. For example (and not byway of limitation), a heated cleaning solution consisting of water fromthe source 104 (heated by the heater 80) mixed with a bleach or othercommercially available sterilant from the source 132 may initially besupplied to the disinfection port 124. Following a predetermined time,while the blood pump 34 continues to operate, the valves 122 and 126 maybe closed, and the valve 128 may be opened so that disinfectant from thesource 134 is drawn through the port 124. Lastly, the valve 128 may beclosed and the valve 122 opened again to provide a final water rinse forthe BTS and the dialyzer 54.

As an optional step (not shown), once the contaminated saline solutionhas been expelled from the BTS and dialyzer, the valve 130 may be openedto allow the blood pump 34 to pump air from the source 136 through theBTS and dialyzer 54 to force a majority of the disinfectant solution 143out of the BTS and the blood chamber 58 of the dialyzer and into thewaste handling port 142. Air may also be pumped through the dialysateline 78 to flush remaining dialysate from the dialysate chamber 60 ofthe dialyzer 54. In this manner, the substantially dry BTS may be moreeasily handled and discarded than a BTS which is still filled with thedisinfectant solution.

The BTS preferably remains attached to the dialyzer 54 during thecleaning/disinfection procedure. While the tubes 52 and 62 of the BTScould be connected together to bypass the dialyzer 54 during thedisinfection procedure, this approach is not recommended for severalreasons. First, an operator runs the risk of contacting the contaminatedsaline solution while disconnecting the dialyzer 54 from the BTS andconnecting the tubes 52 and 62. Additionally, flushing the contaminatedsaline from the blood chamber 58 of the dialyzer 54 makes the dialyzer54 safer to handle. As noted above, dialyzers are frequently reused by asingle patient and thus must be sterilized between uses. While thedisinfection procedure of the present invention may be insufficient tocompletely sterilize the dialyzer for later use, the initialdisinfection which it receives during the disinfection of the BTSreduces the health risks to dialysis machine operators who must latersterilize and recycle the dialyzer. Additionally, if the dialyzer is tobe discarded after the dialysis treatment (i.e., it is disposable), thedisinfection procedure of the present invention may be sufficient todisinfect the dialyzer in addition to the BTS so that both may bediscarded as refuse rather than bio-hazardous waste.

The valves 122, 126, 128 and 130 may operate in a known manner toprevent the contaminated solution within the BTS from being drawnthrough the disinfection port 124 and into the dialysate line 78.Additionally, a valve 144 (FIGS. 5 and 6) is preferably placed withinthe dialysate waste line 82 to prevent contaminants from being drawninto the dialyzer 54 from the waste drain 86. Thus, the BTS may bedisinfected without fear of contaminating the dialysate line 78. This isa significant consideration in light of the fact that the dialysismachine 30 may be used to perform a number of dialysis procedures in aday, while the dialysate hydraulics are typically only cleaned anddisinfected at the start of the day.

Additionally, while the sources 132 and 134 and the pumps 138 and 140are preferably separate from similar sources and pumps used within thedialysate hydraulics to reduce the potential for contaminating thedialysate hydraulics, one skilled in the art may utilize the existingcomponents of the dialysate hydraulics shown in FIG. 5 to attain thefunctionality of the separate components shown in FIG. 6.

The ability to quickly connect the arterial and venous lines 38 and 66to the disinfection port 124 and the waste handling port 142,respectively, is a significant advantage due to the typical desire ofdialysis clinics to treat as many patients as possible in a given day.The BTS and the dialyzer may thus be disinfected in a relatively shorttime period. Indeed, if there is insufficient time to pump the chemicaldisinfectant through the BTS, air from the source 136 may be used toquickly push the majority of the contaminated fluid from both thedialyzer and the BTS. Thus, while the BTS still need to be disposed ofas bio-hazardous waste, it will be easier and safer for an operator tohandle and the clinic will not have to pay for the extra weight of thecontaminated solution.

Of course, the main benefit of the present invention will only beachieved if the BTS can be sufficiently cleaned or disinfected toprevent its being classified as bio-hazardous waste. Thus, for the costof the chemicals used in the disinfection procedure and the timerequired to complete the procedure (during which the dialysis machinecan not be used with a patient), a hospital or dialysis clinic will reapseveral rewards. First, operators who must handle the BTS after theprocedure will no longer be at risk of contacting the contaminatedsolution that remains within the BTS at the conclusion of the dialysistreatment. Secondly, the BTS may now be easily discarded as refuseresulting in a great monetary savings to the dialysis clinic.

Additionally, while the primary benefit of the present invention relatesto disinfecting the BTS, a further significant benefit is achieved bysimultaneously disinfecting the dialyzer. If the dialyzer is to befurther sterilized for later reuse, or if the dialyzer is to bediscarded after the treatment, the initial disinfection which itreceives in conjunction with the BTS will significantly reduce the risksassociated with handling the dialyzer after the treatment.

A presently preferred embodiment of the present invention and many ofits improvements have been described with a degree of particularity.This description is a preferred example of implementing the invention,and is not necessarily intended to limit the scope of the invention. Thescope of the invention is defined by the following claims.

The invention claimed is:
 1. A dialysis machine usable for bothdialyzing blood of a patient in a dialysis treatment and disinfecting acontaminated blood tubing set following use of the blood tubing set inthe dialysis treatment, the blood tubing set having an arterial line anda venous line and adapted to be connected to a blood chamber of adialyzer used during the dialysis treatment, said dialysis machinefurther including a dialysate supplying system for supplying dialysatesolution through a dialysate flow path to a dialysate chamber of thedialyzer during the dialysis treatment, said dialysis machine furthercomprising:a waste drain adapted to be connected to one of the arterialline and the venous line of the blood tubing set following the dialysistreatment; a disinfectant supplying system for preparing a disinfectantsolution and supplying the disinfectant solution in a disinfectant flowpath which is separate and isolated from the dialysate flow path, thedisinfectant solution not being suitable for use as the dialysatesolution; a disinfection port connected in the disinfectant flow pathand adapted to be connected to the other one of the arterial and venouslines of the blood tubing set following the dialysis treatment, saiddisinfection port adapted to conduct the disinfectant solution from thedisinfectant flow path to said other one of the arterial and venouslines; and a pump to pump the disinfectant solution from thedisinfection port through the arterial and venous lines of the bloodtubing set and to the waste drain; and wherein:the separate and isolateddisinfectant flow path preserves the dialysate solution and thedialysate flow path in condition for immediate resumption of anotherdialysis treatment using a new blood tubing set after disinfecting theprevious blood tubing set and without cleaning and disinfecting thedialysate flow path before connecting the new blood tubing set into thedialysate flow path.
 2. A dialysis machine as defined in claim 1 whereinthe waste drain is adapted to be connected to the venous line and thedisinfection port is adapted to be connected to the arterial line.
 3. Adialysis machine as defined in claim 1, wherein the disinfectantsupplying system further comprises:a source of disinfectant solution;and a disinfection source pump to pump the disinfectant solution fromthe disinfectant solution source into the disinfectant flow path to thedisinfection port.
 4. A dialysis machine as defined in claim 3, furthercomprising:a heater to heat the disinfectant solution prior to deliveryfrom the disinfection port.
 5. A dialysis machine as defined in claim 1wherein the pump which pumps the disinfectant solution through the bloodtubing set during disinfection of the blood tubing set also pumps bloodthrough the blood tubing set during the dialysis treatment, the cleaningsolution not being suitable for use as the dialysate solution.
 6. Adialysis machine as defined in claim 1, wherein the disinfectantsupplying system also prepares a cleaning solution for cleaning theblood tubing set and supplies the cleaning solution in the disinfectantflow path.
 7. A dialysis machine as defined in claim 6, wherein thedisinfectant supplying system further comprises:a source of cleaningsolution; and a cleaning solution source pump to pump the cleaningsolution from the cleaning solution source into the disinfectant flowpath to the disinfection port.
 8. A dialysis machine as defined in claim6 wherein the pump which pumps the cleaning solution through the bloodtubing set during cleaning of the blood tubing set also pumps bloodthrough the blood tubing set during the dialysis treatment.
 9. Adialysis machine as defined in claim 7, further comprising:a heater toheat the cleaning solution prior to delivery from the disinfection port.10. A dialysis machine as defined in claim 6, wherein the disinfectantsupplying system is selectively controllable to supply one of either thedisinfectant solution or the cleaning solution through the disinfectantflow path.
 11. A dialysis machine as defined in claim 6, wherein thedisinfectant supplying system also prepares a gaseous fluid for removingthe disinfectant solution and the cleaning solution from within theblood tubing set and supplies the gaseous fluid in the disinfectant flowpath.
 12. A dialysis machine as defined in claim 11, wherein thedisinfectant supplying system further comprises:a source of gaseousfluid; and a pump to pump the gaseous fluid from the gaseous fluidsource into the dialysate flow path to the disinfection port.
 13. Adialysis machine as defined in claim 11, wherein the source of gaseousfluid comprises:an air source; and the disinfectant supplying systemfurther comprises:a valve adapted to supply air from the air source tothe disinfection port.
 14. A dialysis machine as defined in claim 12wherein the gaseous fluid comprises air.
 15. A dialysis machine asdefined in claim 1, wherein the disinfectant supplying system alsoprepares a gaseous fluid for removing the disinfectant solution fromwithin the blood tubing set and supplies the gaseous fluid in thedisinfectant flow path.
 16. A dialysis machine as defined in claim 15wherein the pump which pumps the gaseous fluid through the blood tubingset also pumps blood through the blood tubing set during the dialysistreatment.
 17. A dialysis machine as defined in claim 1 wherein:inputfluid is supplied to both the dialysate preparing system and thedisinfectant supplying system for use in making up the dialysatesolution and the disinfectant solution; the dialysate solution isprepared in the dialysate flow path downstream of a location where theinput fluid is supplied to the dialysate preparing system; and thedisinfectant solution is created in the disinfectant flow pathdownstream of a location where the input fluid is supplied to thedisinfectant supplying system.
 18. A dialysis machine as defined inclaim 17 wherein the input fluid is water.
 19. A dialysis machine asdefined in claim 1, wherein the dialyzer remains connected to the bloodtubing set during disinfection, and the disinfectant solution flowsthrough the blood chamber of the dialyzer during disinfection.
 20. Adialysis machine as defined in claim 18, further comprising:a watersource; and a valve adapted to conduct water from the water source intothe disinfectant flow path and into the dialysate flow path.
 21. Adialysis machine as defined in claim 20, further comprising:a heater toheat the water from the water source prior to conducting the water intothe dialysate and disinfectant flow paths.